Continuously wrapped rotor



"Dec; 13, 1966 F: DORE ET AL 3,290,764

, CONTINUOUSLY WRAPPED ROTOR Filed March 4, 1963 2 Sheets-Sheet 1 IN VEN TOR.

Dem-13, I966 F. DORE ETAL. 3,290,764

Comwuousw WRAPPED ROTOR Filed March 4, 1963 2 Sheets-Sheet 2 from a continuous length of element.

United States Patent 3,290,764 CONTINUOUSLY WRAPPED ROTOR Franklyn Dore and Robert Blechinger, Wellsville, N.Y., assignors, by mesne assignments, to The Air Preheater Company, Inc., a corporation of Delaware Filed Mar. 4, 1963, Ser. No. 262,584 2 Claims. (Cl. 29157.3)

This invention relates to heat exchange apparatus of the rotary regenerative type, and particularly to a unique assembly of continuously wrapped rotor elements and the manner in which they are assembled into a composite body.

A rotary regenerative heat exchanger of the type herein considered usually has a cylindrical rotor divided int-o compartments in which are supported a mass of spaced heat absorbent plates which as the rotor turns are first exposed to a stream of heating gas to absorb heat therefrom and then, upon rotation of the rotor, they are exposed to cooler air or other fluid to be heated whereby the heat absorbed from the heating gas is transferred to the cooler air through the intermediary of the heat absorbent plates.

Most heat exchangers of this type comprise a basic rotor structure which is packed With heat absorbent element in the manner above described. To simplify rotor construction attempts have been made to roll the rotor However, known procedures for preparing such a rotor have resulted in a rotor that was loosely packed, low in heat capacity, difiicult to seal, or otherwise undesirable from an operational standpoint.

The basic object of this invention is therefore to provide for a continuously wrapped rotor for a rotary regenerative heat exchanger that is structurally sound, has a high heat absorbency, and adapts itself readily to an efficient sealing relationship within a rotary regenerative heat exchanger. Another object of this invention is to define the exact steps by which the device of the invention may be effectively produced. These and other objects of theinvention will become more readily apparent when viewed in con-junction with the accompanying drawings in which:

FIGURE 1 is a side elevation of a rotary regenerative heat exchanger constructed according to the invention.

FIGURE 2 is a top plan view of the apparatus as seen from line 2-2 of FIGURE 1.

FIGURE 3 is a diagrammatic presentation of the manner in which the element strips are wrapped on the rotor post.

FIGURE 4 is a top plan view of a modified form of wrapped matrix.

FIGURE 5 is a sectional view as seen from 55 of FIGURE 4 and FIGURE 6 is an enlarged View of the arrangement as viewed from 6-6 of FIGURE 4.

According to the drawing, the regenerative heat exchanger comprises a housing 10 enclosing a rotor 12 that includes a central rotor post 14 and a mass of heat absorbent element 16 carried thereby. A motor 18 moves the rotor about its axis in order that the heat absorbent material is placed alternately in contact with hot gases in duct 20 and cooler gases in duct 22 whereby heat from the hot gases may be transmitted to the cooler gas through the intermediary of the heat absorbent element. 'Sector or end plates 24 at the ends of the housing are formed with openings aligned with ducts 18 and 22 in order that both fluids may be simultaneously directed through the rotor in their predetermined passageways. The flow of the hot gases or cooler air through other than their prescribed passageways is precluded by the use of "ice sealing means on the end edges of the rotor that rub against or pass in spaced relation with the fixed parts of the rotor.

The rotor comprises alternate plane and undulated sheets 26 and 28 having one end secured to the rotor post and the other wrapped continuously about the rotor post until a predetermined diameter of accumulated element layers is attained. During the wrapping process, tension is maintained on one of said element sheets in a direction that resists wrapping in order that a continuous tension may be placed on the rolled elements to obtain a tightly packed element mass throughout the rotor.

Although a matrix of wrapped plane and undulated sheets is to be preferred in most instances, variations in the exact element form or arrangement may be made so long as multiple layers of rolled element provide a plurality of axially disposed flow passageways through the matrix whereby fluid may flow axially therethrough and be precluded from flowing circumferentially around the rotor.

When accumulated layers of heat absorbent element together comprise a matrix of predetermined diameter,

the sheets are severed and the loose ends thereof are secured to the body of the matrix in order that the element will be maintained in its tightly rolled condition. The ends of the element may be secured by spot welding or sheet metal screws, or a circumferential band under tension may be used to encircle the entire matrix to hold it in its rolled form.

A series of radialbars 32 having a length somewhat less than the radius of the rolled matrix are spaced evenly at one end of the rotor and secured to the rotor post. A pair of split rings 38 having a circumference substantially equal to that at the ends of said radial bars are placed in confronting relation at the end of the rotor adjacent the ends of radial bars 32. The split rings 38 thus have a slight gap 42 between ends thereof so as to require compression of the matrix when the split rings are forcibly joined for welding. As the matrix is compressed the split rings 38 are moved radially inward until they abut the ends of the radial bars 32 and thus permit welding together as an integral body.

Radial bars 35 similar in length to bars 32 are positioned at the end of the matrix opposite to and in axial alignment with the bars 32. Tension members 44 are then passed axially through the matrix to extend between bars 3-2 and 35 but are secured initially only to the fixed bars 32. The tension-members 44 are then placed in tension by pulling axially thereon while simultaneously pushing against the face of the matrix thus forcing it tightly against the fixed radial bars 32. While the tension members 44 are thus held in tension they are welded to the radial bars 35. The radially inner ends of bars 35 are then welded to the rotor, while their outer ends are secured to a second pair of split rings 40 whose end edges have been welded together, thus bonding the entire matrix and its support into an integral structural component.

A rotor thus assembled is structurally strong, and the heat absorbent element is maintained under compression with a degree of tightness that precludes leakage laterally between layers of adjacent element sheets. Even though the rotor matrix is held tightly between fixed housing structure and there can be no axial shifting of the element, adjoining element sheets are capable of limited thermal expansion and contraction independently of one another because of the spiral windings of the element strips.

An alternative arrangement for supporting the matrix is illustrated in FIGURES 4, 5 and 6. Here the rotor is comprised of several concentric sections, each one formed from spirally wrapped element sheets that are supported by radial pins 42 extending between radially spaced split rings 38, or as in the case of the innermost section, extending between the ring 38 and rotor post 14. When a section of element being rolled attains a predetermined radial thickness, the element is severed and secured. to the matrix body as before defined. Split rings 38 are secured to the axially spaced edges of the matrix and a plurality of arcuately spaced holes are drilled through spaced rings and the intervening ele ment. Pins 42 preferably formed with a taper fit 45 at the inner end thereof are driven through the holes drilled in the matrix and adjacent split rings and then Welded to the outer ring to hold them securely'in position. Tension straps 48 extending axially between the outer pair of split rings stabilize the entire rotor and help to maintain it in a continuously compressed condition.

While this invention has been defined with reference to the embodiment illustrated in the drawing, it is evident that numerous changes may be made without departing from the spirit of the invention. It is accordingly intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

We claim:

1. The method of forming a perforate matrix for the rotor of a rotary regenerative heat exchanger having rotor structure that includes a central rotor post, said method comprising the steps of securing ends of plane and undulated element strips to said rotor post, placing a tension on one of said elements while wrapping element thereon until accumulated layers attain a predetermined diameter, severing said element strips and securing the severed ends thereof to the rolled matrix, securing a series of radial bars to each end of the rotor post adjacent an end face of said rolled matrix, said. bars being of a length such that they terminate radially inward from the periphery of the rolled matrix, forming bar means arcuately to abut the end edges of said radial bars, compressing said matrix and securing said arcuate bar means to the end edges of the radial bars to form a circumferential band around the periphery of the rotor.

2. The method of forming a perforate matrix for the rotor of a rotary regenerative heat exchanger having rotor structure that includes a central rotor post, said method comprising the steps of securing ends of elongate element strips to said rotor post, wrapping the element continuously theron until accumulated layers of element attain a predetermined diameter, severing said element strips and securing the severed ends thereof to the rolled matrix, securing a series of radial bars to an end of the rotor post adjacent an end face of said rolled matrix, said radial bars to terminate their outer ends at a point spaced radially inward from the periphery of the rolled matrix, arranging a second series of radial bars at the opposite end of said matrix, binding said first series of radial bars to the second series of radial bars with tension members extending axially therebetween securing said second series of bars to said rotor post, compressing said matrix radially until its peripheral edge is in alignmnet with the ends of said radial bars, and placing arcuate bar members around the edges of said matrix and securing them to the ends of said radial bars whereby the rolled matrix is maintained in its compressed condition.

References Cited by the Examiner UNITED STATES PATENTS 1,018,242 2/1912 Heenan 29157.3 1,838,242 12/ 1931 Wilson.- 2,382,386 8/1945 Arms -7 X 2,579,212 12/1951 Stevens 1659 X 2,602,645 7/1954 Benenati et al. 16510 X FOREIGN PATENTS 665,187 1/1952 Great Britain.

JOHN F. CAMPBELL, Primary Examiner.

WHITMORE A. WILTZ, Examiner.

J. D. HOBART, Assistant Examiner. 

1. THE METHOD OF FORMING A PERFORATE MATRIX FOR THE ROTOR OF A ROTARY REGENERATIVE HEAT EXCHANGER HAVING ROTOR STRUCTURE THAT INCLUDES A CENTRAL ROTOR POST, SAID METHOD COMPRISING THE STEPS OF SECURING ENDS OF PLANE AND UNDULATED ELEMENT STRIPS TO SAID ROTOR POST, PLACING A TENSION ON ONE OF SAID ELEMENTS WHILE WRAPPING ELEMENT THEREON UNTIL ACCUMULATED LAYERS ATTAIN A PREDETERMINED DIAMETER, SEVERING SAID ELEMENT STRIPS AND SECURING THE SEVERED ENDS THEREOF TO THE ROLLED MATRIX, SECURING A SERIES OF RADIAL BARS TO EACH END OF THE ROTOR POST ADJACENT AN END FACE OF SAID ROLLED MATRIX, SAID BARS BEING OF A LENGTH SUCH THAT THEY TERMINATE RADIALLY INWARD FROM THE PERIPHERY OF THE ROLLED MATRIX, FORMING BAR MEANS ARCUATELY 